PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of
       this interface may differ (consult the corresponding Linux  manual  page  for  details  of
       Linux behavior), or the interface may not be implemented on Linux.

NAME

       dlclose — close a symbol table handle

SYNOPSIS

       #include <dlfcn.h>

       int dlclose(void *handle);

DESCRIPTION

       The  dlclose()  function shall inform the system that the symbol table handle specified by
       handle is no longer needed by the application.

       An application writer may use dlclose() to make a statement of intent on the part  of  the
       process,  but this statement does not create any requirement upon the implementation. When
       the symbol table handle is closed, the implementation may  unload  the  executable  object
       files  that were loaded by dlopen() when the symbol table handle was opened and those that
       were loaded by dlsym() when using the symbol table handle identified by handle.

       Once a symbol table handle has been closed, an application should assume that any  symbols
       (function  identifiers  and  data  object  identifiers)  made visible using handle, are no
       longer available to the process.

       Although a dlclose() operation is not required to remove any  functions  or  data  objects
       from  the  address  space, neither is an implementation prohibited from doing so. The only
       restriction on such a removal is that no function nor data  object  shall  be  removed  to
       which references have been relocated, until or unless all such references are removed. For
       instance, an executable object file  that  had  been  loaded  with  a  dlopen()  operation
       specifying  the  RTLD_GLOBAL flag might provide a target for dynamic relocations performed
       in the processing of other relocatable objects—in such environments,  an  application  may
       assume  that  no  relocation,  once  made, shall be undone or remade unless the executable
       object file containing the relocated object has itself been removed.

RETURN VALUE

       If the referenced symbol table handle was successfully closed, dlclose() shall  return  0.
       If  handle  does  not  refer  to an open symbol table handle or if the symbol table handle
       could not be closed, dlclose() shall return a non-zero  value.  More  detailed  diagnostic
       information shall be available through dlerror().

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       The following example illustrates use of dlopen() and dlclose():

           #include <dlfcn.h>
           int eret;
           void *mylib;
           ...
           /* Open a dynamic library and then close it ... */
           mylib = dlopen("mylib.so", RTLD_LOCAL | RTLD_LAZY);
           ...
           eret = dlclose(mylib);
           ...

APPLICATION USAGE

       A  conforming  application  should  employ  a symbol table handle returned from a dlopen()
       invocation  only  within  a  given  scope  bracketed  by  a  dlopen()  operation  and  the
       corresponding  dlclose()  operation. Implementations are free to use reference counting or
       other techniques such that multiple calls to  dlopen()  referencing  the  same  executable
       object file may return a pointer to the same data object as the symbol table handle.

       Implementations are also free to re-use a handle. For these reasons, the value of a handle
       must be treated as an opaque data type by the application, used only in calls  to  dlsym()
       and dlclose().

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       dlerror(), dlopen(), dlsym()

       The Base Definitions volume of POSIX.1‐2017, <dlfcn.h>

COPYRIGHT

       Portions  of  this  text  are  reprinted  and  reproduced in electronic form from IEEE Std
       1003.1-2017, Standard for Information Technology -- Portable  Operating  System  Interface
       (POSIX),  The  Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by
       the Institute of Electrical and Electronics Engineers, Inc and The  Open  Group.   In  the
       event  of  any  discrepancy  between this version and the original IEEE and The Open Group
       Standard, the original IEEE and The Open Group  Standard  is  the  referee  document.  The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

       Any  typographical  or  formatting errors that appear in this page are most likely to have
       been introduced during the conversion of the source files to man page  format.  To  report
       such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .